A little-known method of measuring the volume of small objects based on Archimedes principle is described, which involves suspending an object in a waterfilled container placed on electronic scales. The suspension technique is a variation on the hydrostatic weighing technique used for measuring volume. The suspension method was compared with two other traditional water displacement methods of measuring volume -i.e. placing an object in a measuring cylinder and recording the rise in the water level and immersing the object in a water-filled container with an overflow spout to record the volume of overflow. The accuracy and precision of the three methods was compared using 10 accurately machined PVC cylinders ranging in volume from 1.5 to 15.7 ml. The mean difference between the actual and measured volumes was 3.3 ± 7.3%, -1.6 ± 7.2% and 0.03 ± 0.45%, for the level, overflow and suspension methods respectively. Each measurement was repeated twice to obtain the reproducibility of the three displacement techniques. The reproducibility was -1.7 ± 8.5%, 0.09 ± 3% and -0.04 ± 0.43% for the level, overflow and suspension techniques respectively. The results show that the suspension technique is more accurate and precise than the traditional water displacement methods and is more accurate than measuring volume using Vernier calliper measurements. IntroductionThe purpose of this article is to present an adaptation of the hydrostatic technique for measuring the volume of small objects. Hydrostatic weighing is familiar to those in metrology laboratories but from the author's experience does not appear well-known in education circles (i.e. in schools and universities). After a fairly extensive search of physics text books and the scientific literature over a number of years, no direct references to the technique have been discovered 1 .

Our computerized system has the capacity to be used in conjunction with any standard two-dimensional ultrasound scanner in order to measure volume. Lung volume measurement may be useful in predicting pulmonary hypoplasia.

The southern Appalachians represent a landscape characterized by locally high topographic relief, steep slopes, and frequent mass movement in the absence of significant tectonic forcing for at least the last 200 Ma. The fundamental processes responsible for landscape evolution in a post-orogenic landscape remain enigmatic. The non-glaciated Cullasaja River basin of south-western North Carolina, with uniform lithology, frequent debris flows, and the availability of high-resolution airborne lidar DEMs, is an ideal natural setting to study landscape evolution in a post-orogenic landscape through the lens of hillslope-channel coupling. This investigation is limited to channels with upslope contributing areas >2.7 km 2 , a conservative estimate of the transition from fluvial to debris-flow dominated channel processes. Values of normalized hypsometry, hypsometric integral, and mean slope vs elevation are used for 14 tributary basins and the Cullasaja basin as a whole to characterize landscape evolution following upstream knickpoint migration. Results highlight the existence of a transient spatial relationship between knickpoints present along the fluvial network of the Cullasaja basin and adjacent hillslopes. Metrics of topography (relief, slope gradient) and hillslope activity (landslide frequency) exhibit significant downstream increases below the current position of major knickpoints. The transient effect of knickpoint-driven channel incision on basin hillslopes is captured by measuring the relief, mean slope steepness, and mass movement frequency of tributary basins and comparing these results with the distance from major knickpoints along the Cullasaja River. A conceptual model of area-elevation and slope distributions is presented that may be representative of post-orogenic landscape evolution in analogous geologic settings. Importantly, the model explains how knickpoint migration and channelhillslope coupling is an important factor in tectonically-inactive (i.e. post-orogenic) orogens for the maintenance of significant relief, steep slopes, and weathering-limited hillslopes.

We present an interpretation of the crustal velocity structure of the New England Appalachians and the Adirondack Mountains based on a seismic refraction/wide‐angle reflection experiment in eastern North America extending from the Adirondacks in New York State through the northern Appalachians in Vermont and New Hampshire to central Maine. Modeling of the eastern portion of the profile within the New England Appalachians shows a subhorizontal layered crust with upper crustal velocities ranging from 5.5 to 6.2 km/s, a midcrustal velocity of 6.4 km/s, and a lower crustal velocity of approximately 6.8 km/s. Crustal thickness increases from 36 km beneath Maine to 40 km in Vermont. Little evidence is seen for structures at depth directly related to the White Mountains or the Green Mountains. A major lateral velocity change in the upper and mid crust occurs between the Appalachians and the Adirondacks. This boundary, projecting to the surface beneath the Champlain Valley, dips to the east beneath the Green Mountains and extends to a depth of ∼25 km below the eastern edge of the Connecticut Valley Synclinorium in Vermont. The Tahawus Complex, a series of strong horizontal reflections at 18–24 km depth beneath the Adirondack Highlands, is seen to dip eastward beneath Vermont. Upper crustal rocks in the Adirondack Mountains have Poisson's ratios of 0.28±0.01 that can be correlated with the Marcy Anorthosite. Pois son's ratios of 0.24±0.01 calculated for rocks of the Connecticut Valley Synclinorium indicate a siliceous upper crust in Vermont. The lower crust is considered to be best represented by intermediate to mafic granulites; a high Poisson's ratio (0.26–0.27) tends to support a mafic lower crust in the New England Appalachians. This seismic refraction/wide‐angle reflection experiment provides further evidence for the obduction of the allochthonous western Appalachian units onto Grenvillian crust above a zone of detachment that penetrates at least to midcrustal depths and was the locus of successive Paleozoic thrusting.

Objective To measure fetal lung volume using a computer based, enhanced, 3‐dimensional ultrasound imaging system. Design An observational study. Setting The Fetal Medicine Unit at Guys Hospital, London. Participants Twenty healthy women with a singleton pregnancy between 24 and 36 weeks of gestation were scanned on one occasion during pregnancy using an ultrasound based 3‐dimensional imaging system. All delivered at term with weights above the 10th centile for gestation. Results Total lung volume increased exponentially with gestational age. Right lung volume measured consistently greater than left lung volume. Conclusions The use of this new enhanced 3‐dimensional imaging system allows for estimations of fetal lung volume. Preliminary data confirm that fetal lung volume, measured by a computerised 3‐dimensional ultrasound imaging system increased exponentially with gestational age. The use of this system has obvious application in the further study of lung growth in utero and possible clinical application in disease states where fetal lung growth may be impaired.